I have basically always shot the tightest choke I could find until I bought a hasting .655 for my remington 870 and my pattern was all over the place. I recently bought a mossberg and I am shooting the factory xtra full turkey choke wich I believe is a .685 or .690. Even though mossbergs are backbored I thought that the choke would be to open but I am now getting the best patterns I have ever got at 40 yards so I think it helps to have a choke that is a little open but you would't want to go tofar I don't think. I guess I need to try the regular full choke and see what it will do.